laptop-kernel/include/rxrpc, branch master

rxrpc: Move the packet.h include file into net/rxrpc/

2017-07-21T10:00:20Z

Move the protocol description header file into net/rxrpc/ and rename it to protocol.h. It's no longer necessary to expose it as packets are no longer exposed to kernel services (such as AFS) that use the facility. The abort codes are transferred to the UAPI header instead as we pass these back to userspace and also to kernel services. Signed-off-by: David Howells

rxrpc: Implement service upgrade

2017-06-05T13:30:49Z

Implement AuriStor's service upgrade facility. There are three problems that this is meant to deal with: (1) Various of the standard AFS RPC calls have IPv4 addresses in their requests and/or replies - but there's no room for including IPv6 addresses. (2) Definition of IPv6-specific RPC operations in the standard operation sets has not yet been achieved. (3) One could envision the creation a new service on the same port that as the original service. The new service could implement improved operations - and the client could try this first, falling back to the original service if it's not there. Unfortunately, certain servers ignore packets addressed to a service they don't implement and don't respond in any way - not even with an ABORT. This means that the client must then wait for the call timeout to occur. What service upgrade does is to see if the connection is marked as being 'upgradeable' and if so, change the service ID in the server and thus the request and reply formats. Note that the upgrade isn't mandatory - a server that supports only the original call set will ignore the upgrade request. In the protocol, the procedure is then as follows: (1) To request an upgrade, the first DATA packet in a new connection must have the userStatus set to 1 (this is normally 0). The userStatus value is normally ignored by the server. (2) If the server doesn't support upgrading, the reply packets will contain the same service ID as for the first request packet. (3) If the server does support upgrading, all future reply packets on that connection will contain the new service ID and the new service ID will be applied to *all* further calls on that connection as well. (4) The RPC op used to probe the upgrade must take the same request data as the shadow call in the upgrade set (but may return a different reply). GetCapability RPC ops were added to all standard sets for just this purpose. Ops where the request formats differ cannot be used for probing. (5) The client must wait for completion of the probe before sending any further RPC ops to the same destination. It should then use the service ID that recvmsg() reported back in all future calls. (6) The shadow service must have call definitions for all the operation IDs defined by the original service. To support service upgrading, a server should: (1) Call bind() twice on its AF_RXRPC socket before calling listen(). Each bind() should supply a different service ID, but the transport addresses must be the same. This allows the server to receive requests with either service ID. (2) Enable automatic upgrading by calling setsockopt(), specifying RXRPC_UPGRADEABLE_SERVICE and passing in a two-member array of unsigned shorts as the argument: unsigned short optval[2]; This specifies a pair of service IDs. They must be different and must match the service IDs bound to the socket. Member 0 is the service ID to upgrade from and member 1 is the service ID to upgrade to. Signed-off-by: David Howells

rxrpc: Add tracepoint for ACK proposal

2016-09-23T14:49:19Z

Add a tracepoint to log proposed ACKs, including whether the proposal is used to update a pending ACK or is discarded in favour of an easlier, higher priority ACK. Whilst we're at it, get rid of the rxrpc_acks() function and access the name array directly. We do, however, need to validate the ACK reason number given to trace_rxrpc_rx_ack() to make sure we don't overrun the array. Signed-off-by: David Howells

rxrpc: Rewrite the data and ack handling code

2016-09-08T10:10:12Z

Rewrite the data and ack handling code such that: (1) Parsing of received ACK and ABORT packets and the distribution and the filing of DATA packets happens entirely within the data_ready context called from the UDP socket. This allows us to process and discard ACK and ABORT packets much more quickly (they're no longer stashed on a queue for a background thread to process). (2) We avoid calling skb_clone(), pskb_pull() and pskb_trim(). We instead keep track of the offset and length of the content of each packet in the sk_buff metadata. This means we don't do any allocation in the receive path. (3) Jumbo DATA packet parsing is now done in data_ready context. Rather than cloning the packet once for each subpacket and pulling/trimming it, we file the packet multiple times with an annotation for each indicating which subpacket is there. From that we can directly calculate the offset and length. (4) A call's receive queue can be accessed without taking locks (memory barriers do have to be used, though). (5) Incoming calls are set up from preallocated resources and immediately made live. They can than have packets queued upon them and ACKs generated. If insufficient resources exist, DATA packet #1 is given a BUSY reply and other DATA packets are discarded). (6) sk_buffs no longer take a ref on their parent call. To make this work, the following changes are made: (1) Each call's receive buffer is now a circular buffer of sk_buff pointers (rxtx_buffer) rather than a number of sk_buff_heads spread between the call and the socket. This permits each sk_buff to be in the buffer multiple times. The receive buffer is reused for the transmit buffer. (2) A circular buffer of annotations (rxtx_annotations) is kept parallel to the data buffer. Transmission phase annotations indicate whether a buffered packet has been ACK'd or not and whether it needs retransmission. Receive phase annotations indicate whether a slot holds a whole packet or a jumbo subpacket and, if the latter, which subpacket. They also note whether the packet has been decrypted in place. (3) DATA packet window tracking is much simplified. Each phase has just two numbers representing the window (rx_hard_ack/rx_top and tx_hard_ack/tx_top). The hard_ack number is the sequence number before base of the window, representing the last packet the other side says it has consumed. hard_ack starts from 0 and the first packet is sequence number 1. The top number is the sequence number of the highest-numbered packet residing in the buffer. Packets between hard_ack+1 and top are soft-ACK'd to indicate they've been received, but not yet consumed. Four macros, before(), before_eq(), after() and after_eq() are added to compare sequence numbers within the window. This allows for the top of the window to wrap when the hard-ack sequence number gets close to the limit. Two flags, RXRPC_CALL_RX_LAST and RXRPC_CALL_TX_LAST, are added also to indicate when rx_top and tx_top point at the packets with the LAST_PACKET bit set, indicating the end of the phase. (4) Calls are queued on the socket 'receive queue' rather than packets. This means that we don't need have to invent dummy packets to queue to indicate abnormal/terminal states and we don't have to keep metadata packets (such as ABORTs) around (5) The offset and length of a (sub)packet's content are now passed to the verify_packet security op. This is currently expected to decrypt the packet in place and validate it. However, there's now nowhere to store the revised offset and length of the actual data within the decrypted blob (there may be a header and padding to skip) because an sk_buff may represent multiple packets, so a locate_data security op is added to retrieve these details from the sk_buff content when needed. (6) recvmsg() now has to handle jumbo subpackets, where each subpacket is individually secured and needs to be individually decrypted. The code to do this is broken out into rxrpc_recvmsg_data() and shared with the kernel API. It now iterates over the call's receive buffer rather than walking the socket receive queue. Additional changes: (1) The timers are condensed to a single timer that is set for the soonest of three timeouts (delayed ACK generation, DATA retransmission and call lifespan). (2) Transmission of ACK and ABORT packets is effected immediately from process-context socket ops/kernel API calls that cause them instead of them being punted off to a background work item. The data_ready handler still has to defer to the background, though. (3) A shutdown op is added to the AF_RXRPC socket so that the AFS filesystem can shut down the socket and flush its own work items before closing the socket to deal with any in-progress service calls. Future additional changes that will need to be considered: (1) Make sure that a call doesn't hog the front of the queue by receiving data from the network as fast as userspace is consuming it to the exclusion of other calls. (2) Transmit delayed ACKs from within recvmsg() when we've consumed sufficiently more packets to avoid the background work item needing to run. Signed-off-by: David Howells

rxrpc: Update protocol definitions slightly

2016-09-08T10:10:11Z

Update the protocol definitions in include/rxrpc/packet.h slightly: (1) Get rid of RXRPC_PROCESS_MAXCALLS as it's redundant (same as RXRPC_MAXCALLS). (2) In struct rxrpc_jumbo_header, put _rsvd in a union with a field called cksum to match struct rxrpc_wire_header. (3) Provide RXRPC_JUMBO_SUBPKTLEN which is the total of the amount of data in a non-terminal subpacket plus the following secondary header for the next packet included in the jumbo packet. Signed-off-by: David Howells

rxrpc: Randomise epoch and starting client conn ID values

2016-09-04T20:41:39Z

Create a random epoch value rather than a time-based one on startup and set the top bit to indicate that this is the case. Also create a random starting client connection ID value. This will be incremented from here as new client connections are created. Signed-off-by: David Howells

rxrpc: Static arrays of strings should be const char *const[]

2016-04-11T19:34:40Z

Static arrays of strings should be const char *const[]. Signed-off-by: David Howells Signed-off-by: David S. Miller

rxrpc: Be more selective about the types of received packets we accept

2016-03-04T15:56:06Z

Currently, received RxRPC packets outside the range 1-13 are rejected. There are, however, holes in the range that should also be rejected - plus at least one type we don't yet support - so reject these also. Signed-off-by: David Howells

rxrpc: Keep the skb private record of the Rx header in host byte order

2016-03-04T15:53:46Z

Currently, a copy of the Rx packet header is copied into the the sk_buff private data so that we can advance the pointer into the buffer, potentially discarding the original. At the moment, this copy is held in network byte order, but this means we're doing a lot of unnecessary translations. The reasons it was done this way are that we need the values in network byte order occasionally and we can use the copy, slightly modified, as part of an iov array when sending an ack or an abort packet. However, it seems more reasonable on review that it would be better kept in host byte order and that we make up a new header when we want to send another packet. To this end, rename the original header struct to rxrpc_wire_header (with BE fields) and institute a variant called rxrpc_host_header that has host order fields. Change the struct in the sk_buff private data into an rxrpc_host_header and translate the values when filling it in. This further allows us to keep values kept in various structures in host byte order rather than network byte order and allows removal of some fields that are byteswapped duplicates. Signed-off-by: David Howells

RxRPC: Handle VERSION Rx protocol packets

2015-04-01T15:31:26Z

Handle VERSION Rx protocol packets. We should respond to a VERSION packet with a string indicating the Rx version. This is a maximum of 64 characters and is padded out to 65 chars with NUL bytes. Note that other AFS clients use the version request as a NAT keepalive so we need to handle it rather than returning an abort. The standard formulation seems to be: built --

for example: " OpenAFS 1.6.2 built 2013-05-07 " (note the three extra spaces) as obtained with: rxdebug grand.mit.edu -version from the openafs package. Signed-off-by: David Howells